graph API: eliminate unnecessary indentation

This change improves the calculation of the amount of horizontal
padding, so that there is always exactly 1 space of padding.
Previously, most commits had 3 spaces of padding, but commits that
didn't have any children in the graph had only 1 space of padding.

Signed-off-by: Adam Simpkins <adam@adamsimpkins.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/graph.c b/graph.c
index 616e18b13f496cd97bce5333b6c7655ae3cfa2f0..9d6ed30b0bef22bd8b56da9a12688c760b661776 100644 (file)
--- a/graph.c
+++ b/graph.c
@@ -60,6 +60,12 @@ struct git_graph {
         * this number)
         */
        int num_parents;
+       /*
+        * The width of the graph output for this commit.
+        * All rows for this commit are padded to this width, so that
+        * messages printed after the graph output are aligned.
+        */
+       int width;
        /*
         * The next expansion row to print
         * when state is GRAPH_PRE_COMMIT
@@ -207,13 +213,48 @@ static void graph_insert_into_new_columns(struct git_graph *graph,
        graph->num_new_columns++;
 }
 
+static void graph_update_width(struct git_graph *graph,
+                              int is_commit_in_existing_columns)
+{
+       /*
+        * Compute the width needed to display the graph for this commit.
+        * This is the maximum width needed for any row.  All other rows
+        * will be padded to this width.
+        *
+        * Compute the number of columns in the widest row:
+        * Count each existing column (graph->num_columns), and each new
+        * column added by this commit.
+        */
+       int max_cols = graph->num_columns + graph->num_parents;
+
+       /*
+        * Even if the current commit has no parents, it still takes up a
+        * column for itself.
+        */
+       if (graph->num_parents < 1)
+               max_cols++;
+
+       /*
+        * We added a column for the the current commit as part of
+        * graph->num_parents.  If the current commit was already in
+        * graph->columns, then we have double counted it.
+        */
+       if (is_commit_in_existing_columns)
+               max_cols--;
+
+       /*
+        * Each column takes up 2 spaces
+        */
+       graph->width = max_cols * 2;
+}
+
 static void graph_update_columns(struct git_graph *graph)
 {
        struct commit_list *parent;
        struct column *tmp_columns;
        int max_new_columns;
        int mapping_idx;
-       int i, seen_this;
+       int i, seen_this, is_commit_in_columns;
 
        /*
         * Swap graph->columns with graph->new_columns
@@ -259,11 +300,13 @@ static void graph_update_columns(struct git_graph *graph)
         */
        seen_this = 0;
        mapping_idx = 0;
+       is_commit_in_columns = 1;
        for (i = 0; i <= graph->num_columns; i++) {
                struct commit *col_commit;
                if (i == graph->num_columns) {
                        if (seen_this)
                                break;
+                       is_commit_in_columns = 0;
                        col_commit = graph->commit;
                } else {
                        col_commit = graph->columns[i].commit;
@@ -290,6 +333,11 @@ static void graph_update_columns(struct git_graph *graph)
        while (graph->mapping_size > 1 &&
               graph->mapping[graph->mapping_size - 1] < 0)
                graph->mapping_size--;
+
+       /*
+        * Compute graph->width for this commit
+        */
+       graph_update_width(graph, is_commit_in_columns);
 }
 
 void graph_update(struct git_graph *graph, struct commit *commit)
@@ -368,22 +416,12 @@ static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb)
         *
         * This way, fields printed to the right of the graph will remain
         * aligned for the entire commit.
-        *
-        * This computation results in 3 extra space to the right in most
-        * cases, but only 1 extra space if the commit doesn't have any
-        * children that have already been displayed in the graph (i.e.,
-        * if the current commit isn't in graph->columns).
         */
-       size_t extra;
-       size_t final_width = graph->num_columns + graph->num_parents;
-       if (graph->num_parents < 1)
-               final_width++;
-       final_width *= 2;
-
-       if (sb->len >= final_width)
+       int extra;
+       if (sb->len >= graph->width)
                return;
 
-       extra = final_width - sb->len;
+       extra = graph->width - sb->len;
        strbuf_addf(sb, "%*s", (int) extra, "");
 }